In operating a motor vehicle, kinetic energy of the motor vehicle may be converted into electrical energy. This is referred to as recuperation of kinetic energy. Recuperation can be used in a motor vehicle with exclusively electric drive, wherein during the recuperation process an electric machine operates as a generator or the drive can be used in a motor vehicle with a hybrid drive application if, therefore, an internal combustion engine and a further drive in the form of an electric machine together form the drive of the motor vehicle.
In the context of the open-loop and/or closed-loop control of a hybrid drive it is known to provide open-loop or closed-loop control of a hybrid drive in a motor vehicle predictively on the basis of a communication of the motor vehicle with positionally fixed and/or moving opposite parties by selecting an operating strategy. The operating strategy can, as an operating state, also differentiate and set, inter alia, the recuperation of braking energy.
In the case of motor vehicles which are operated exclusively or largely with an electric drive, a significant feature is the range, such as how far the motor vehicle can travel, without an electrochemical energy accumulator (a battery) of the motor vehicle having to be connected to a terminal (outside the motor vehicle) and charged.
During braking, energy is lost in the form of thermal energy. By recuperation, a proportion of the kinetic energy can, however, be converted into forms of energy which permit subsequent use in order to operate the motor vehicle. The recuperation process usually increases the range of the motor vehicle. Quite specific severity of braking (measured as a negative acceleration) during which the recuperation process is optimal, will then occur; a specific quantity of energy per time unit (power density) can be input into an energy accumulator, and given excessively severe braking more kinetic energy is obtained from the motor vehicle than can be stored simultaneously in the energy accumulator, and in the case of excessively weak braking the braking distance is too long.
It is to be assumed here that the braking process can be optimized. Methods for optimizing such a braking process are known, for example from DE 10 2007 010 188 A1 and DE 10 2008 024 622 A1. This involves, in particular, the activation or deactivation of brakes and brake circuits.